Figure 2.

Unrooted median-joining networks based on 1162, bp sequences of the mitochondrial control region for (a) breeding (n=162) and (b) wintering (n=138) tufted ducks. Samples from the breeding season were grouped as Europe, Western Siberia (west of river Ob), Eastern Siberia and Eastern Asia. Wintering ducks were partitioned into hypothetical subpopulations in south-eastern and north-western Europe and in Asia (Iran, China and Japan). The size of the circles is proportional to the number of individuals with a particular haplotype. Asterisks mark the haplotypes observed in H5N1-positive tufted ducks sampled on European wintering grounds (see text). Note that the corresponding haplotypes are also indicated in (a) to illustrate their spatial distribution on the breeding grounds.